<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>我的</title>
</head>

<body class="df aic jcc">
  <!-- 主要内容 -->
  <main class="flex overflow">
   <div id="countdown" class="fwb tac cf">3</div>
  </main>
</body>

</html>